The Democratic Senatorial Campaign Committee launched its first independent expenditure ad of the cycle Tuesday, the premiere installment in a $3.6 million buy in Arkansas on behalf of Sen. Mark Pryor.

The ad pushes a theme Democrats have worked for months to sew into the race — that Republican Rep. Tom Cotton can't be trusted. www.youtube.com/watch?v=6JSmcLIOFho

"When they needed funding, Tom Cotton was the only member of Congress from Arkansas who voted against it," a former hospital social worker says in the ad.

The DSCC has previously run coordinated ads in Arkansas, Montana and Iowa, but this is the first ad from its independent expenditure unit. The National Republican Senatorial Committee's IE ran digital ads during the Mississippi primary, but it has not yet run TV ads.

The race is rated Tilts Republican by the Rothenberg Political Report/Roll Call.